The production of biopharmaceutical products normally involves a cultivation process of bacteria, yeasts, animal, plant, and/or transgenic cells. The fermentation or cultivation process produces a broth that contains the biomass, the desired product and many other components in solution. Among the other components, one may find contaminants and product related impurities. These may, for example, include media components (antibiotics, glucose, amino acids), viruses, endotoxins, DNA, aggregates and host cell proteins.
In order to produce the biopharmaceutical product with the required safety and efficacy requirements, typically, multiple purification steps are used to remove the contaminants and product related impurities. Two modes of operation can be distinguished for chromatographic processes:                Flow Through; the process solution is passed through the chromatography bed and one or more contaminants bind to the resin. The process solution, with the product of interest dissolved in it, passes through the bed and is collected with a significant reduction in contaminants;        Bind & Elute: the product of interest is preferentially bound to the resin and the process solution with the majority of contaminants dissolved will pass through the bed. The product of interest is then eluted in a later stage and can be collected highly purified.        
The advantages of membrane adsorbers have been successfully exploited in Flow Through operations. For Bind & Elute type of chromatography, however, the nature of membrane adsorbers represents a few significant disadvantages, in particular, its low volumetric capacity: the amount of product that can be bound to a membrane adsorber per unit volume of membrane material. Accordingly, a desire exists to provide a method wherein the membrane absorbers can be used while improving the yield of a product of interest.